Skeet, trap, sporting clays, and hunting are just a few of the increasingly popular sports which require the shooting of a moving target with a shotgun. Indeed, as of 1993, there were over 17,000 members in the National Skeet Shooting Association, the governing body of all skeet shooting in the United States. The Amateur Trap Shooting Association, which serves as the governing body for all registered trap shoots, boasts a membership of over 100,000. Sporting clays, which developed in England in 1925, although having had a somewhat slower start, has too seen an increase in popularity since 1985. As to the sport of hunting, in 1989 the U.S. Fish and Wildlife Service estimated there were nearly 16 million licensed hunters, which makes hunting one of the most popular sports in the United States.
In skeet, targets called "birds" are thrown at speeds of about 75 mph (120 kmph) by mechanical or electrical "traps" from a pair of houses, one low and one high, which are spaced-apart a distance of about 37 yards (34 m). From each of a group of eight stations positioned along an arc extending between the houses, the skeet shooter shoots at a target thrown from the high house, and then at one thrown from the low house. At stations one, two, six and seven, however, the shooter also shoots at a double, which consists of a pair of targets released simultaneously, one from the high house and one from the low house. For these doubles, as the target thrown from the high house travels at a relatively steeper trajectory than that of the target thrown from the low house, the targets are made to intersect at a point near the middle of the field. To successfully hit a target, the skeet shooter must lead the target to compensate for its speed, angle, and distance. At each station of a skeet field, there is known to be a unique, predetermined amount of lead that must be taken to break the target.
In trap, like skeet, a shooter attempts to hit targets thrown at speeds of about 75 mph (120 kmph). The targets in trap, however, are thrown away from the shooter at five different angles from a pit located below ground level in the middle of a field. Shooting from five successive stations positioned in an arcuate row behind the pit, the trap shooter, like the skeet shooter, must lead each target to compensate for its speed, angle, and distance.
In sporting clays, targets, which may be of five different sizes and may range in color from white, yellow, orange, or black, are thrown from a wooded setting at a higher rate of speed than either trap or skeet targets in order to simulate actual hunting conditions. The sporting clays shooter shoots the targets, which are released as either singles, following pairs, report doubles or true doubles, from various stations along a pre-arranged course. Unlike in skeet or trap, however, the sporting clay shooter may not mount the shotgun until the target is thrown and becomes completely visible. Because of the speed, size, and colors of the targets, coupled with the varied backgrounds of the wooded or other natural settings around which the sporting clays range is designed, complete concentration on the target is of the utmost importance. As in trap and skeet, the sporting clay shooter too must lead the target to compensate for its speed, angle, and distance. So too in the other, somewhat lesser known shotgun sports of tower shoots, flushes, crazy quail and quail walks, and in the more internationally-known sports of Olympic Trap and Skeet, pigeon shooting, and driven pheasants, must the shooter import the principals of target concentration and lead compensation.
In the sport of hunting, the target, an animal, usually is naturally camouflaged and difficult to see, and generally moves along an unpredictable path at changing speeds. Wooded areas which generally exhibit a mottled, cluttered background, and open fields which may provide a bright background, also affect the hunter's ability to spot game. Accordingly, as in the other shooting sports, it is important that the hunter devote full concentration on the target and, when hunting running game, compensate for the speed, angle, and distance of such game.
Beginners in any of the shooting sports quickly discover that shooting a moving target is quite difficult. Such difficulty is compounded with respect to the shooting sports which employ a shotgun, as such sports typically involve a smaller and faster moving target be it a clay, a rabbit, or a bird. Generally, a shotgun has a smooth-bored barrel with a relatively large inner diameter as compared to a rifle. The shotgun shell houses a group of small, metal pellets called shot which, when fired, assume a fountain-like spread as they leave the barrel. This fountain-like pattern, called a shotstring, makes it somewhat easier to hit a moving target as providing the shooter with a larger region of possible impact, as compared to a single projectile, within which the target may be intercepted. An experienced shooter will aim at the target using a smooth, continuous motion. A small steel or plastic bead-sight attached to the barrel of the gun typically is provided to aid the shooter in aiming the shotgun at the target.
To achieve successful results, the shooter must mount and aim the shotgun properly. When mounting the shotgun, the shooter must bring the butt-end of the stock to the shoulder and the side of the stock to the face. In this position, the shooter's eye which is nearest to the stock is made to look directly along what is termed a "sight axis" which extends along the top barrel of the shotgun to the bead-sight. Once the shotgun is properly mounted, the shooter's head, preferably, is not moved with respect to the gun. In this way, a consistent body position is achieved, and the gun is maintained at the same position relative to the shooter's eye for use as a reference while the shooter is concentrating and focusing visually on a target moving farther afield. In aiming the gun at the target, the shooter preferably keeps both eyes opened to obtain a wider range of vision. Such vision gives the shooter additional time for target acquisition and concentration. Indeed, a shooter attempting to hit a moving target while using only one eye for aiming is greatly restricted in vision and, consequently, in ability to hit the target.
As aforementioned, in order to hit a target, the shooter must lead the target to compensate for its speed, angle and distance. To obtain a proper lead, the shooter must concentrate intensely on the target, and yet still must be aware of the location of the end of the shotgun as such end is used as a reference as to where the gun is pointed. At least with respect to skeet, trap, and sporting clays, there are three basic methods of obtaining the proper lead to successfully hit a target: the pass through method, the acceleration method, and the sustained lead method. In using the pass through method, the shooter starts the gun behind the target, swings the gun to overtake and pass through the target, and then fires. Thus, to successfully hit a target using the pass through method, the shooter must concentrate on the target and pass the bead-sight on the muzzle of the shotgun through the target.
In using the acceleration method, the shooter aims the gun directly at the target and tracks it through the air. When ready to shoot, the shooter accelerates the gun past the target and then fires. Thus, to successfully hit a target using the acceleration method, the shooter must place the bead-sight of the shotgun on the target, and then track the target with the sight before accelerating the gun to shoot.
Lastly, in using the sustained lead method, the movement of the gun is started simultaneously at target release, which movement is maintained to effect a constant lead in front of the target. With the sustained lead method, the shooter may fire at the target at anytime during its flight. To successfully break a target using the sustained lead method, the shooter must concentrate on the target, and yet remain aware of the orientation of the barrel of the shotgun as a reference point to verify that the correct lead has been taken to break the target. At least for skeet shooting, the sustained lead method currently is considered the most accurate method of leading a target. However, in utilizing any of the lead methods, the shooter must intensely concentrate on the target while remaining aware of the location of the tip of the barrel of his shotgun.
For all of the above shooting techniques, the eyes of the shooter are concentrated at the target while the arms, head, and eyes are moved in a sweeping motion across the shooting field. For the most part, to aim at the elevated targets, the eyes are looking upwardly and may, for example, scan across the position of the sun or bright, reflecting objects such as buildings. Thus, as the shooter concentrates upon the target, different brightness intensities are encountered. These brightness variations, whether direct or reflected have an effect at the eye station of the shooter.
In view of the foregoing, it will be understood that participants in shooting sports are called upon to perceive with the eye and brain a target which may be moving at speeds of upwards of 70 mph (110 kmph) and at varying distances. Although the human brain is in function similar to a super computer, the eye from which it receives information is comparatively primitive. In gross anatomy, the eye is a simple lens which focuses on an image plane called the retina, which is a delicate, multi-layered, light-sensitive membrane lining the inner surface of the eye connected by the optic nerve to the brain. Through changes in the curvature of the lens brought about by its elasticity and contraction of the ciliary, i.e., accommodation, muscles of the eye, light rays are focused on the retina where they stimulate sensory receptors. With advancing age, the eye becomes increasingly difficult to focus due to a loss in the elasticity of the lens and weakening of ciliary muscles, which results in a visual condition referred to as presbyopia.
Further, as light within the visual spectrum is considered "broad spectrum" as composed of many wavelengths or "colors," the lens of the eye is not always able to accommodate such that all of the wavelengths are focused exactly on the focal plane at the retina. Such accommodation inability is known to result in what is termed "chromatic aberration." Chromatic aberration is a phenomenon associated with broad-spectrum light wherein the eye will provide a focus position for a given object depending upon the wavelength of the light emanating from the object to be focused. Inasmuch as in any normal viewing situation, the image of an object is contained in light having a variety of wavelengths, essentially only one such wavelength can be focused precisely at the retina. Thus, all the other wavelengths will be focused at some focal length forward or rearward of the retina. The farther any given wavelength is focused from the retina, the more blurred its image becomes. With respect to focusing problems caused by either chromatic aberrations or advancing age, the brain is called upon to process images resulting from the distorted information received from the eye.
For shooters, the visual input data to the brain additionally is compromised by the inability of the eye to simultaneously focus both on the near bead at the tip of the shotgun and on the distant target itself, nor with both on the high detail area of the retina, namely the fovea. Thus, the shooter must concentrate and focus clearly on one object, the target for example, while the other object, i.e., the tip of the gun is seen in less detail. However, because of training, an experienced shooter will have a mental awareness as to the position of the gun sight and visual concentration may remain upward and outward.
All intelligent shooters wear glasses, and most wear specially-designed shooting glasses. Principally, shooting glasses are worn for safety as shot may ricochet from the target, and the target itself may present a hazard as its fragments when hit. In this regard, the lenses of shooting glasses typically are formed of a polymeric material, such as an acrylic, a polycarbonate, or the like, which resists shattering upon impact. An ancillary, but in some respects no less important, function is that of improving the visual acuity of the shooter. For shooters requiring corrective lenses, the need for shooting glasses is obvious. However, even shooters having 20/20 vision benefit from wearing shooting glasses. In this regard, shooting glasses generally are designed with lenses tinted with pigmentation in the mid-spectral range, i.e., at some level of yellow. Such pigments are selected as it is accepted that a mid-spectral tint reduces chromatic aberration for improved focus on the target.
Although the shooting glasses heretofore known in the art have gained acceptance as being tinted to reduce chromic aberration and/or for use as protective sunglasses, vision problems nevertheless have persisted, especially with competition shooters. In particular, eye-related problems such as, eye muscular fatigue, headaches, and eye redness occur, such problems generally being identified as asthenopia, i.e., eyestrain or tiring of the eyes due to fatigue of the ciliary or extraocular muscles. As explained by Gilson et at., U.S. Pat. No. 4,470,673, the disclosure of which is expressly incorporated herein by reference, a number of environmental factors have been determined to contribute to asthenopia, a most prominent one being glare. In general, glare phenomena are considered to include a broad range of physiological and psychological factors, as well as physical conditions which combine to make the brightness conditions within any visual environment contribute either favorably or unfavorably to seeing conditions. For example, variations in brightness may influence the visibility of an object of interest in a task such as shooting, and result in a decreased ease of "seeing". Direct glare generally is caused by the viewing of an object of low luminance or brightness, such as a clay target or an animal, in the presence of a considerably higher luminance object, such as the sun. Although a significant reduction in visibility may not be noticed, a general feeling of discomfort often is manifested under direct glare situations. In this regard, the reader's attention is directed to Guth, S. K., "Discomfort Glare," Amer. J. Optom. and Arch. Amer. Acad. Optora., 38, 247 (1961). Glare also may be occasioned indirectly as a result of light being reflected to the eye from the ground particularly where the shooter is looking upwardly at a target. Consider, for example, ground covered by snow, gravel, or calm water surface.
Another factor contributing to sighting difficulties for shooters is the high degree of concentration demanded. That is, it is known that whenever the gaze of the eyes is changed to an object of a different brightness level, some period of time is required for the eyes to adapt to the different luminance level. Indeed, the greater the difference in luminance, the longer the eyes will take to adapt. Thus, the focus of a shooter onto a relatively low luminance target, after having been focused on the usually brighter surroundings, necessitates the adaptation of the eyes to the lower luminance level. Such adaptation, when repeated target after target during shooting competitions or the like, has been known to lead to ocular fatigue and a decreased visual efficiency.
In addition to asthenopia, another vision problem related to overhead glare which plagues shooters and hunters is that of loss of contrast caused, for the most part, by a phenomena known as "veiling luminance." As again explained by Gilson et al., U.S. Pat. No. 4,470,673, veiling luminance results from various imperfections in the structuring of the human eye. These imperfections lead to a light scattering effect which, in turn, causes a distribution of glare-generated illuminance across the retina. Such illuminance, although developing in non-retinal regions of the eye, is known to affect the macula lutea of the retina, i.e., the yellow spot in the center of the retina which, in turn, overlaps the fovea, or central depression of the macula lutea, a tiny area of optimal acuity. The resulting effect on vision is one wherein the overall illuminance at the fovea is elevated, decreasing the contrast, which is essential to image resolution, sharpness, and clarity.
Heretofore, manufacturers of shooting glasses and the like have only addressed the subject matter of brightness at the shooting station by utilizing tinted lenses. As for the use of tinted lenses, the filtering effect achieved by way of a simple transmission reduction generally results in an overall diminished light transmission.